Rotary engine

ABSTRACT

A rotary combustion engine has a toroidal cylinder chamber in which two pairs of pistons are displaceable in one direction of rotation and one pair with respect to the other. The two pairs of pistons are respectively connected to two independent shafts coaxial with the axis of the cylinder chamber. The two pairs of pistons define in the cylinder chamber two diametrically opposed main chambers into which a fuel mixture is fed and ignited to cause expansion of the main chambers. The engine comprises further two pairs of arms fixed respectively to the two shafts and projecting radially therefrom and a pair of rollers pivotally connected by links to the outer ends of the arms and constrained to move along an endless stationary track extending about the axis of the cylinder chamber in a plane normal thereto and a flywheel connected to one of the shafts.

United States Patent 1191 Taurozzi 1451 Dec. 17, 1974 ROTARY ENGINE [75] Inventor: Eduardo H. Taurozzi, Junin,

Argentina [73] Assignees: Armando Taurozzi; Juan Carlos Taurozzi; Santiago Sanchez Elia, all of Buenos Aires, Argentina; part interest to each i [22] Filed; Oct. 6, 1972 [2]] Appl. No.: 295,497

[30] Foreign Application Priority Data Oct. 11. 1971 Argentina 238429 521 US. (:1 123/847,418/3141 /38. [5]] Int. Cl F02b 55/14 [58] Field of Search 418/8, 37, 38, 35; I 123/847 [56] References Cited UNITED STATES PATENTS I 957,631 5/1910 Stewart".. 418/33 X 1.163.142 12/1915 Gooding. 4l8/37X 1.298.839 4/1919 Weed 418/37 x 1.328.410 .1/1920 Weed 418/35 1.904.892

4/1933 Trube 4l8/38 3,280,803 10/1966 Sabet ..4'l8/37X 3,670,705 6/1972 Saito: l2 3/8.47

I Primary E.\"aminerC. J. Husar Assistant Etamincr-Leonard Smith Attorney. Agent, or Firm-Michael S. Striker 5 7] ABSTRACT A rotary combustion engine has a toroidal cylinder chamber in which two pairs of pistons are displaceable in one direction of rotation and one pair with respect to the other. The two pairs-of pistons are respectively v connected to two-independent shafts coaxial with the axis of the cylinder chamber. The two pairs of pistons .define in the cylinder chamberttwo diametrically opposed main chambers into which a fuel mixture is fed 1 and ignited to cause expansion of the main chambers.

The engine comprises further two pairs of arms fixed respectively to the two shafts and projecting radially therefrom and a pair of rollers pivotally connected by linksto the outer ends of the arms and constrained to A .move along an endless stationary track extending about the axis of the cylinder chamber in a plane normal thereto and a flywheel'connected to one of the shafts.

g 6 Claims, 8 Drawing Figures PATENTEU BEE] 71974.

SHEET S I]? 6 PATENTED I 3, 854.457

- SHEET 6 OF 6 1 ROTARY ENGINE The toroidal cylinder rotary engine is a new mechanical arrangement which allows practicing therewith the known Otto, Diesel, and semi-Diesel or Sabathe cycles,

said arrangement also being useful as an impeller, suc- Specific advantages of this engine worthy of note include: sealing of combustion'chambers is relatively simple; high torque at low revolutions; reduced weight/- power ratio; modification of the compression ratio is possible without substantial changes in the engine; and, finally, the engines remarkable mechanical simplicity.

The present invention has an object a rotary engine comprising a toroidal cavity housing therewithin four pistons oppositely joined in pairs, by means of respective piston carrying discs coplanar with said toroidal cavity; the first pair of pistons, called leading pistons, are linked through the corresponding piston-carrying disc to a first shaft, normal to the toroidal cavity plane, the axis of which passes through the center of symmetry of said toroidal cavity; this first shaft carries, mounted on one end thereof, an inertia flywheel, so that the assembly that includes the flywheel, the first shaft and corresponding piston-carrying disc rotates with an approximately uniform circular motion around the axis of the first shaft, once the engine has been started, the first shaft leading the uniform movement to a housing, called control box", wherein by means of a connecting rod and jointed arms mechanism regularity of said movement is altered, resulting movement being transmitted at the outlet of said box to the second pair of pistons, designated as trailing pistons, by means of a second shaft, coaxially disposed relative to the first shaft, and the second piston-carrying disc, so that the pair of trailing pistons will follow the leading pistons continuously changing the position relative thereto, between a maximum distance position and a maximum closeness position. Thus four variable volume chambers are defined, of which the two opposed chambers located between the leading pistons (linked to the flywheel) at the front and the trailing pistons (receiving movement from the box) at the back, are used to perform said cycle. Expansions and contractions of each chamber always occur at the same section of the toroidal cavity, enabling inlet and outlet port means to be located, said parts being uncovered when each chamber registers with the cylinder sector in question. it is also possible to conveniently locate the spark plugs or injectors, according to the cycle adopted, in accordance to the number of strokes per cycle and with the number of cycles per revolution.

In four-stroke engines, while admission is taking place in one chamber, combustion occurs in the other and when the first is effecting compression, in the second one exhaust is being accomplished. In two-stroke engines both chambers work in parallel. During the firing stroke the pair of leading pistons (linked to the flywheel) must receive the power developed by reaction, transferring itto the flywheel, while the pair of trailing pistons must be prevented from receding within the cylinder; during the compression stroke, the trailing pistons must advance their run relative to the leading pistons,against the resistance opposed by the mixture confined within the chamber. As a consequence of the above, and due to the trailing pistons being linked to a lesser inertia assembly, the pair of trailing pistons will always tend to retard their run relative to the leading pistons; this effect is used in the control box, within which two pairs of diammetrically opposed arms are housed, each pair being radially linked to one of said coaxial shafts, which independently relate them with the two pairs of pistons.

Since the trailing pistons tend to retard their run relative .to the leading pistons, the arms linked to the second shaft will always tend to modify in the same direction the angle they form with the arms linked to the first shaft. The free end of each arm is jointed to a connecting rod and, in turn, the free end of each connecting rod corresponding to each arm connected to the second shaft is jointed with the free end of the connecting rod corresponding to one of the two arms linked to the first shaft in a manner'such that two rhomboids having pivoted vertices are formed, symmetrical relative to the axis of the shafts, each of said rhomboids having as 3 tion of the pistons will be' altered. As said angle tends to change in only one direction while the engine is running, each of the outer joints will tend to shift in one direction only, so that by placing a closed guiding contour in the path of the outer joint it is possible to continuously control the distance separating said joint from the axis of the coaxial shafts and, consequently,

the angle between the. arms and the relative run of the two pairs of pistons. Said guiding contour may consist in a bearing mounted on the pin of each outer joint the displacement of which it is desired to control, rolling on the surface of a closed roller track, or else may'consist in a pinion mounted on the same pin and engaging a closed rack, the parameters of they primitive circle being identical in both cases and calculated to pennanently control the volume of the chambers. The arms linked to the pair of leading pistons through the first shaft should be longer than those linked to the pair of driven pistons through the second shaft, so that the resultant of the actions they exert on the outer vertex of the rhomboid, through the respective connecting rods,

has a direction allowing the freely rotating element to The couple of chambers defined between the trailing pistons at the front and the leading pistons at the back, called counterchambers, may be employed as supercharging or scavenging pumps, in which case fresh air inlet conduits are opened, as well as conduits suitably communicating the counterchambers with the chambers, this operation being controlled by means of a mechanism comprising valves, springs and a ribbed plate for controlling opening and closing of valves, rotary movement of said plate being derived from the first shaft.

Sealing of the combustion chambers is effected by means of conventional rings mounted on the pistons, plus a set of three circular packing gland rings, inserted between the two piston-carrying discs and between these and the block. These rings are forcefully retained against the discs, so that escape of gases towards the shaft housing is prevented.

Three embodiments of the subject invention will be described hereinafter, with the sole purpose of graphically exemplifying the operating principle, nowise limiting however the scope of the invention, and refering to the following drawings, wherein: I

FIG. 1 shows a longitudinal section of the engine, taken along the plane of simmetry.

FIG. 2 shows a cross-section of the engine along the line AA, FIG. 1. 7

FIG. 3 shows a cross section of the engine along the line BB, FIG. 1.

FIG. 4 isa detail of FIG. 1 showing how the toroidal cavity is sealed by means of circular packing rings.

FIG. 5 is a longitudinal section of a second embodiment of the invention, taken along its axis of simmetry, incorporating a supercharging device.

FIG. 6 is a cross-section taken along section line DD in FIG. 5.

FIG. 7 relates to a third embodiment of the invention and shows a longitudinal section taken along the plane of simmetry of a revolution converter device added to it.

FIG. 8 shows a cross section taken along the line EE of FIG. 7.

In these Figures, equal parts are indicated by the same reference numbers.

All the Figures show a four-stroke rotary engine operating on the Otto cycle. The coolant employed is air, while the fuel used is gasoline. Auxiliary mechanisms are the same as used in conventional engines, to wit: (a) a fuel feeding system, comprising a fuel tank, a fuel pump, a conventional carburetor and an air filter; (b) an ignition system, comprising a battery, an ignition coil, a distributor and a spark plug, and (c) a lubricating system, comprising a lubricating oil reservoir, a filter and a lube pump.

In'the first embodiment of the invention, the engine block is divided into two half-blocks, l and 2 in FIG. 1, solidly joined together, which define therebetween a toroidal cavity housing therein two pairs of pistons, 3 and 4. The block has been divided in two half-blocks in order to allow machining of thetoroidal cavity. The outside surface shows cooling fins for disperse the heat generated by the cycle. At the back of half-block l a cover 5 is secured, also having cooling fins.

Half-block 1 has two bores, 6 and 7, communicating the toroidal cylinder to atmosphere, the first of which is the admission conduit, while the second bore is the exhaust conduit. There is also a spark plug access recess 8 and a through-bore forming a housing for a shaft 9. Each of these bores extend through cover 5. In halfblock 2 a through-bore receives two coaxial shafts 9 and 11, respectively made integral with piston pairs 4 and 3, in FIG. 2, by means of respective piston-carrying discs and 61. The side surface of these pistoncarrying discs form part of the toroidal cylinder (FIG. 1 Between the piston-carrying discs 60 and 61 and the block a set of packing rings 37, 38 and (FIG. 4) is inserted, and between the pistons and the block a set of piston rings is located, the purpose of which is to seal the combustion chambers.

Shaft 11 is integral with a second shaft 12 through a splined joint, said shaft 12 extending through a housing defined by a casing 13 and its cover 28, there being located within said housing two radial arms 19 (FIGS. 1 and 3), integral with shaft 12 and diametrically opposed. At the front end of shaft 12 a flywheel 26 is mounted. Shaft 9 is integral with a further shaft 10 by means of a conical coupling and a through bolt 27.

Shaft 10 is coaxially arranged within shaft 12 and carries two radially opposed arms 23 (FIG. 3), located inside the same housing as arms 19, passing through two longitudinal grooves in shaft 12. This combination of coaxial shafts is mounted on a set of roller bearings 29 to 35.

The pair of arms 19 (FIGS. 1 and 3) carry in their corresponding free ends respective connecting or links 15, pivotally mounted by means of pins 18. In turn, connecting rods 15 are pivotally joined to a further pair of connecting rods 20 by means of pins 17, extending at both sides and carrying mounted in each of their ends a rotary means in form of a roller or ball bearing 16. Connecting or links 20 are pivotally joined to arms 23 by means of a set of pins 21, FIG. 3, Connecting rod 15 has a double head in its pivotal connection with arm 19, as with connecting rod 20 in its connection with rod 15, and arm 23 in its connection with connecting rod 20.

Casing 13 is in turn solidly connected to half-block 2 through bolts received in lodgings 24, FIG. 3. An outer roller track 14 and a further inner roller track 22 are integrally linked to casing 13, while an outer roller track 14 and an inner roller track 22, identical with roller tracks 14 and 22, respectively, are firmly mounted on cover 28. Each of roller bearings 16 simultaneously bear on the surface of corresponding roller tracks 14 or 14' and 22 or 22.

The engine assembly is mounted on legs 25, which are provided with springs 36 that prevent undue vibration. The second embodiment comprises the same component parts as the first embodiment, but also includes new additional parts which shall be mentioned at once and which enable supercharging the engine: a circular disc 44, FIG. 5, solidly connected to shaft 12, carrying a series of bosses 45; a valve 41 normally retained against its seat 40 by the action of a spring 43, said valve stopping an air admission conduit 42; and a discharge conduit 46, also shut off by means of a valve retained on its seat by the action of a spring, said conduit opening into a mixture admission conduit 6.

The third embodiment also comprises the same component parts as the first embodiment, but incorporates further parts added with the purpose of multiplying the number of complete four stroke cycles described. per piston revolution.

A ring gear 51 is mounted by means of a conical coupling on shaft 9, the extension whereof is supported by a bearing 53. Said bearing 53 is mounted on a support 57, and the head of a bolt 52 axially screwed into shaft 9 serves as a seat for said bearing 53. In turn, a ring gear 50 is mounted on shaft 11 through a disc integral with said shaft 1 1 and bolts 63, while a bearing 58 is inserted between said ring 50 and shaft 9. Ring gear 51 engages a pinion 48, solid with a shaft 9', coaxially disposed relative to a further shaft 11', having in turn a pinion 49 mounted thereon, close to its rear-end, which meshes with ring gear 50. Shaft 11' bears by its rear end on a bearing 54, which in turn seats on a boss disposed to such purpose in casing 13, while shaft 9 seats on a bearing 56 resting on support 57. A bearing 55 is inse rted between coaxial shafts9 and 11 in order to maintain the assembly duly aligned.

Operation of the engine is the following: inside the toroidal cavity, following a single direction of movement, the pair of pistons 3, hereinafter designated leading pistons, and the pair of pistons 4, hereinafter designated trailing pistons, move. Each of the two combustion chambers (A and B, FIG. 2) is defined by a leading piston, at the front, and a trailing piston, behind.

These chambers shift within the toroidal cavity as a consequence of the displacement of the pistons. Leading pistons 3 are coupled, by means of shafts l 1 and 12, to the engine flywheel, so that their movement is approximately uniform. This is not the case with trailing pistons 4, which follow the leading pistons by constantly changingtheir positions relative thereto.

Since leading pistons 3 are integral with arms 19, through shafts 11 and 12, and trailing pistons 4 with arms 23 through shafts 9 and 10, relative position between said pistons is attained by means of the housing defined by casing 13, hereinafter called control box, by the relative position between arms 19 and 23. These arms are pivoted one with the other by means of connecting rods and and pins 17,18 and 21. By varying the distance separating pin 17 from the axis of symmet'ry of the engine the angle formed between the arms 19 and 23, and consequently the relative position between the pistons, in the'toroidal cavity will be modified.

Arms 23, hereinafter called the driven arms, which are indirectly related to the trailing pistons 4, are coupled to shaft 10 in such a manner that they run ahead of the pair of arms 19, hereinafter called leading arms," which are indirectly integral with the leading pistons 3. In other words, even though relative position between leading and trailing pistons is reproduced by arms 19 and 23, due to the above described mechanical arrangement, the smaller the angle between the arms, the greater the distance between the pistons, and vice versa.

Leading arms 19 will tendto maintain their movement because they are linked through tubular shaft 12 to flywheel 26. On their part, driven arms 23 will tend to constantly reduce the angle they form with leading arms 19, due to the fact that trailing pistons 4 will tend to increase the distance separating them from leading pistons 3,. This is due to the following: (a) during one stroke, while in one chamber compression is being effected, in the other scavenging is taking place, so that the pair of trailing pistons 4 meets resistance to relative advance regarding leading pistons 3; (b) during the next stroke, in one chamber combustion occurs while in the other admission takes place, so that the pair of trailing pistons will be forced to retard relative to the pair of leading pistons; (c) additionally to said causes, trailing pistons 4 are integrally linked to a combination of lesser inertia than the leading pistons 3 and therefore the first will tend to retard their run relative to the sec- Consequently, driven arms 23, that are substantially shorter than leading arms 19, exert through connecting rods 20 and pins 17 an action on bearings 16 which is approximately normal to the roller track 14 and which maintains them bearing thereon. On the other hand, leading arms 19, being sustancially. longer than driven arms 23, exert a force on bearing 16, through connecting rod 15 and pin 17, which forces said bearing 16 to roll on track 14 in the same direction of rotation as the pistons. In other words, the relative lengths of arms and connecting rods are such that the resultant of action exerted on the outer joint, defined by pin 17, can be resolved into two forces, one of which is normal to roller track 14 is a direction maintaining roller bearing 16 resting thereon, the other being tangential to said track, in the direction of rotation of the engine. Thus, reaction of the trackprevents the tendency of the trailing pistons to retard regarding the leading pistons.

Configuration of roller tracks 14 and 14 allows control of the angle of the arms form between each other, and accordingly the volume of the combustion chamber. When the joints defined by pinsv l7 confront the corresponding zones of the roller tracks 14 or 14, distance whereof to the axis of symmetry of the engine is minimal, the angle between the arms shall be maximal and therefore the combustion chamber volume shall be minimal. Conversely, when the same joints confront the zone of the same roller tracks distance whereof to the axis of symmetry of the engine is maximal, the angle between the arms shall be minimal and consequently the volume of said combustion chambers shall be maximal.

Both chambers start and terminate each of the four strokes at a given place of the toroidal cavity, according to which ports 6 and 7 and spark plug 8 have been located.

It is possible to modify the maximum volume of the combustion chambers by simply replacing roller tracks 14 or 14' with others having different parameters or by modifying length inter-relationships of the arms and connecting rods.

To ensure proper operation of the control device,

tracks 14 and 14 can take the form of racks, the roller bearings being replaced in such a case with pinions enmeshing with the racks.

When the engine stops, the force tending to maintain bearings 16 on the tracks 14 and 14 disappears, so that it becomes possible for the bearings to detach themselves therefrom. To preclude this possibility, a set of inner tracks 22 and 22' is provided.

Airtightness of the combustion chambers is obtained by means of a set of rings mounted on each piston, plus the set of packing glands 37, 38 and 39, received in respective cavities in the block and piston-carrying disc 61. The rings are pushed against the discs and 61 by means of springs.

The several parts related to the trailing pistons 4 are manufactured from light alloys so as to reduce the assembly inertia.

As stated before, combustion chambers A and B (FIG. 6) are defined between each leading piston 3, at the front, and each trailing piston 4 at the back. There are, however, a further pair of chambers, C and D (FIG. 6), defined between each trailingpiston 4 at the front and each leading piston 3 at the back, which vary their volume oppositely to the main or combustion chambers. Chambers C and D shall hereinafter be designated the counter-chambers. This fact is employed to operate scavenging or supercharging of the main chambers, according to the embodiment adopted. In FIGS. 5 and 6, corresponding to a second embodiment of the invention, a method is illustrated for effecting supercharging of the engine. When in main chamber A scavenging takes place (sector a, FIG. 6) and in chamber B compression is effected (sector "y the counterchambers are increasing their volumetric capacity, this effect being used to draw fresh air from atmosphere via an admission conduit 42 (FIG. 5). This conduit is normally stopped by a valve 41, kept against its seat 40 by the force of a spring 43.

Opening of the valve is governed by means of a plate 44, integral with leading shaft '12, said plate having bosses 45 acting on valve 41 and against the load of spring 43.

During the cycle of admission in chamber A (sector B), and combustion in chamber B (sector 8), counterchamber D effects a reduction of its volumetric capacity. During this period, and by means of a conduit 46 opening into admission conduit 6, air dislodged from counterchamber D is used for supercharging the main chamber. In conduit 46 there is also a valve, similar to valve 41, also provided with a spring, the valve being operated by plate 44.

As we have shown, each of the main chambers completes a cycle, that is, the four strokes, in one revolution within the toroidal cylinder. According to the third embodiment of the invention, it is possible to increase the number of cycles per revolution, inserting a revolution converter box between the pistons and the control box. FIGS. 7 and 8 therefore illustrate how said reduction is operated. Other components and parts in the engine are the same as in the first embodiment. A ring gear 50, integral with leading shaft 11, meshes with a pinion 49, integral with a shaft 11', coaxial with a further shaft 9. A further ring gear 51, integral with the driven shaft 9, meshes with a second pinion 48, integral with inner shaft 9', coaxial with shaft 11. Shafts 9 and 11' extend into the control box, identical to the one formerly described, except that the leading arms are now integral with the inner shaft 11, and driven arms 23 are here integral with outer shaft 9, because the shaft linked to the leading pistons is no longer the outer shaft but is now the inner one, after the reduction box, and conversely, the shaft linked to the trailing pistons is no longer the inner one but has become the outer shaft.

Bearings 53, 54, 55, 56 and 58 serve as support for the shafts reaching into the reduction box. Particularly, bearings 53 and 56 are held in position by a support 57. The head of bolt 52 serves as seat for bearing 53.

Transmission ratio between ring gears 50 and 51, and pinions 48 and 49, is a multiple of two, so that for each revolutionof the pistons the control mechanism effects a whole number of complete cycles.

ln-the toroidal cylinder there shall be as many spark plugs and admission and exhaust conduits as indicated by the multiplication ratio between ring gears 50 and 51 and pinions 48 and 49.

With this device, for each revolution of the pistons the control mechanism will have completed as many cycles as indicated by the reduction ratio between pinions and ring gears, and thus in the toroidal cavity the same number of four-stroke cycles will have taken place. This device permits obtaining a more regular run and increasing the power delivered by the engine for a same number of revolutions in the flywheel.

What I claim is:v

1. In a rotary engine, a combination comprising two I rotary independent coaxial shafts; stationary means defining a toroidal chamber extending about the axis of said shafts; two pairs of pistons displaceable in one direction of rotation in said chamber and one pair with respect to the other pair; means for respectively connecting one pair of said pistons to each other and to one of said shafts and the other pair of said pistons to each other and to the other of said shafts; a first pair of arms integral with one of said shafts and projecting substantially opposite each other radially therefrom; a second pair of arms integral with the other of said shafts and projecting substantially opposite each other radially. from said other shaft, each of said arms having a radially outer end; only two rollers arranged substantially diametrically opposite to each other between the outer ends of said first and second pair of arms; a pair of links for each roller pivotally connecting the respective roller to the respective outer ends of said arms so' that said rollers may move radially with respect to the axis of said shafts upon angular movement of said first and second pairs of arms with respect to each other; stationary endless cam means extending about said axis substantially in a plane normal'thereto, said cam means being engaged by said rollers; one of said pair of pistons leading in said one direction of rotation, and inertia means fixedly connected to that shaft which is connected to said one pair of pistons, said one pair of pistons defining with said other pair of pistons in said toroidal chamber two diametrically opposite main chambers, and two opposite further chambers; first port means successively communicating with said main chambers during movement of said pistons in said one direction and expansion of said main chambers for feeding a fuel mixture into the respective main chamber; fuel mixture firing means for igniting said mixture in the respective main chamber; and second port means successively communicating with said main chambers for discharging combustion gases therefrom during contraction of said main chambers, said further chambers expanding during contraction of said main chambers and vice versa but do not receive fuel from said first port means.

2. A combination as defined in claim 1, wherein the arms of one of said pairs are longer than the arms of said other pair.

3. A combination as defined in claim 1 wherein said means for respectively connecting one pair of pistons to each other and to one of said shafts, and the other pair of pistons to each other and to the other of said shafts, comprise a pair of discs extending normal to said axis and being fixedly connected to the respective pistons and shafts, and including at least three packing rings in sealing contact with said discs.

4. In a rotary engine, a combination comprising two rotary independent coaxial shafts; stationary means defining a toroidal chamber extending about the axis of said shafts; two pairs of pistons displaceable in one direction of rotation in said chamber and one pair with respect to the other pair; means for respectively connecting one pair of pistons to each other and to one of said shafts and the other pair of pistons to each other and the other of said shafts; a first pair of arms integral with one of said shafts and projectingwsubstantially opposite to each other radially therefrom; a second pair of arms integral with the other of said shafts and projecting transverse to said first pair of arms opposite to each other from said other shaft, each of said arms having a radially outer end; only two rotary means arranged substantially diametrically opposite each other between the outer ends of said first and said second pair of arms; a pair of links for each rotary means pivotally connecting the respective rotary means to respective outer ends of said arms so that each rotary means may move radially with respect to the axis of said shafts upon angular movement of said first and second pairs with respect to each other; stationary endless track means extending about said axis substantially in a plane normal thereto, said track means being engaged by said rotary means; inertia means connected to that shaft to which one pair of said pistons is fixedly connected which leads in said one direction of rotation, said one pair of pistons defining with said other pair of pistons in said toroidal chamber two diametrically opposed main chambers and two opposed further chambers; first port means successively communicating with said main chambers during movement of said pistons in said one direction and expansion of said main chambers for feeding a fuel into the respective main chamber, said further chamber expanding during contraction of said main chamber andvice versa; first conduit means for admitting air intosaid further chambers during expansion of the latter; second conduit means connecting said further chambers with said main chambers; first and second valve means respectively located in said first and second conduit means and each movable between an open and a closed position for respectively permitting and preventing passage of air therethrough; valve operating means connected to said first shaft for opening said first and closing said second valve means during expansion of said further chambers and for opening said second and closing said first valve means 1 during contraction of said further chambers for feeding air from said further chambers into said main chambers; firing means for igniting the fuel air mixture in the respective main chamber; and second port means successively communicating with said main chambers for discharging combustion gases therefrom during contraction of said main chambers.

5. A combination as defined in claim 4, wherein said rotary means is a roller. 6. A combination as defined in claim 4, and including spring means for normally holding said valve means in one of the positions thereof, said valve operating means comprising a disc fixed to said first shaft for rotation therewith and provided with a plurality of projections arranged to successively engage said first and second valve means during rotation of said shaft to move said valve means from the one to the other of said positions. 

1. In a rotary engine, a combination comprising two rotary independent coaxial shafts; stationary means defining a toroidal chamber extending about the axis of said shafts; two pairs of pistons displaceable in one direction of rotation in said chamber and one pair with respect to the other pair; means for respectively connecting one pair of said pistons to each other and to one of said shafts and the other pair of said pistons to each other and to the other of said shafts; a first pair of arms integral with one of said shafts and projecting substantially opposite each other radially therefrom; a second pair of arms integral with the other of said shafts and projecting substantially opposite each other radially from said other shaft, each of said arms having a radially outer end; only two rollers arranged substantially diametrically opposite to each other between the outer ends of said first and second pair of arms; a pair of links for each roller pivotally connecting the respective roller to the respective outer ends of said arms so that said rollers may move radially with respect to the axis of said shafts upon angular movement of said first and second pairs of arms with respect to each other; stationary endless cam means extending about said axis substantially in a plane normal thereto, said cam means being engaged by said rollers; one of said pair of pistons leading in said one direction of rotation, and inertia means fixedly connected to that shaft which is connected to said one pair of pistons, said one pair of pistons defining with said other pair of pistons in said toroidal chamber two diametrically opposite main chambers, and two opposite Further chambers; first port means successively communicating with said main chambers during movement of said pistons in said one direction and expansion of said main chambers for feeding a fuel mixture into the respective main chamber; fuel mixture firing means for igniting said mixture in the respective main chamber; and second port means successively communicating with said main chambers for discharging combustion gases therefrom during contraction of said main chambers, said further chambers expanding during contraction of said main chambers and vice versa but do not receive fuel from said first port means.
 2. A combination as defined in claim 1, wherein the arms of one of said pairs are longer than the arms of said other pair.
 3. A combination as defined in claim 1, wherein said means for respectively connecting one pair of pistons to each other and to one of said shafts, and the other pair of pistons to each other and to the other of said shafts, comprise a pair of discs extending normal to said axis and being fixedly connected to the respective pistons and shafts, and including at least three packing rings in sealing contact with said discs.
 4. In a rotary engine, a combination comprising two rotary independent coaxial shafts; stationary means defining a toroidal chamber extending about the axis of said shafts; two pairs of pistons displaceable in one direction of rotation in said chamber and one pair with respect to the other pair; means for respectively connecting one pair of pistons to each other and to one of said shafts and the other pair of pistons to each other and the other of said shafts; a first pair of arms integral with one of said shafts and projecting substantially opposite to each other radially therefrom; a second pair of arms integral with the other of said shafts and projecting transverse to said first pair of arms opposite to each other from said other shaft, each of said arms having a radially outer end; only two rotary means arranged substantially diametrically opposite each other between the outer ends of said first and said second pair of arms; a pair of links for each rotary means pivotally connecting the respective rotary means to respective outer ends of said arms so that each rotary means may move radially with respect to the axis of said shafts upon angular movement of said first and second pairs with respect to each other; stationary endless track means extending about said axis substantially in a plane normal thereto, said track means being engaged by said rotary means; inertia means connected to that shaft to which one pair of said pistons is fixedly connected which leads in said one direction of rotation, said one pair of pistons defining with said other pair of pistons in said toroidal chamber two diametrically opposed main chambers and two opposed further chambers; first port means successively communicating with said main chambers during movement of said pistons in said one direction and expansion of said main chambers for feeding a fuel into the respective main chamber, said further chamber expanding during contraction of said main chamber and vice versa; first conduit means for admitting air into said further chambers during expansion of the latter; second conduit means connecting said further chambers with said main chambers; first and second valve means respectively located in said first and second conduit means and each movable between an open and a closed position for respectively permitting and preventing passage of air therethrough; valve operating means connected to said first shaft for opening said first and closing said second valve means during expansion of said further chambers and for opening said second and closing said first valve means during contraction of said further chambers for feeding air from said further chambers into said main chambers; firing means for igniting the fuel air mixture in the respective main chamber; and second port means successively communicating with said main chambers for dischargiNg combustion gases therefrom during contraction of said main chambers.
 5. A combination as defined in claim 4, wherein said rotary means is a roller.
 6. A combination as defined in claim 4, and including spring means for normally holding said valve means in one of the positions thereof, said valve operating means comprising a disc fixed to said first shaft for rotation therewith and provided with a plurality of projections arranged to successively engage said first and second valve means during rotation of said shaft to move said valve means from the one to the other of said positions. 